The present invention relates generally to safety equipment, and more particularly is a method of protecting a helmet shell and interrupting airflow around the helmet that utilizes an airflow interrupter strip that is attached to a helmet of a user.
In motor cycling, as well as in any type of freeway speed (above 50 mph) activity in which the participants wear helmets, one of the problems the riders face is the buffeting and suction lift caused by laminar air flow around the helmet.
As illustrated in FIGS. 1 and 2, air flow around a smooth helmet is laminar. At freeway speeds, this creates a low pressure area at the sides and rear of the helmet, leading to a suction force. The suction forces on the sides of the helmet tend to buffet the rider""s head back and forth. This has a strong detrimental effect on the rider""s balance, comfort, and vision. The suction forces at the rear of the helmet create a lifting effect that tends to raise the rear of the helmet, thereby driving the front of the helmet over the user""s eyes. This also has a direct detrimental effect on the rider""s vision, which is clearly very undesirable when moving at freeway speeds. The lifting effect""s driving the helmet forward also tends to uncomfortably tighten the chin strap of the helmet.
Many devices in the prior art are directed to controlling air flow in the interior of a helmet to cool the user""s head while he wears the helmet. Examples of this type of device are the xe2x80x9cBicyclists Helmet with Air Flow and Perspiration Controlxe2x80x9d by Sundahl et al., U.S. Pat. No. 4,434,514, issued Mar. 6, 1984; and the xe2x80x9cHelmetxe2x80x9d by Kamiya et al., U.S. Pat. No. 4,519,099, issued May 28, 1985. Both these devices use a plurality of vents to direct the air flow within the helmet.
At least one prior art device has recognized and addressed the buffeting problem in a light helmet used at high speed. The xe2x80x9cAerodynamic Bicycle Helmetxe2x80x9d by Rotzin, U.S. Pat. No. 5,023,958, shows a soft shell helmet that utilizes several ridges across an upper front portion of the helmet to disrupt the air flow around the helmet. The device is directed to foam-only helmets (col. 1, lines 55-56). The fact that the helmets are constructed solely from foam allows the manufacturers to easily include the ridges in the outer surface.
However, due to the restrictions of manufacturing processes as well as for aesthetic considerations, most if not all hard shell helmets currently manufactured have a smooth outer surface. The smooth outer surface provides for a laminar local air flow. Furthermore, there is no teaching in the prior art that would provide a device that would allow the user to adjust the air flow interruption to his personal taste or depending on the immediate circumstances. Further, there is no method taught in the prior art to provide a removable air flow interrupter.
Moreover, many helmets are painted and/or decorated quite elaborately to the user""s tastes. The appearance of the helmet is subject to damage if the helmet is accidentally dropped or if it were to fall off the handlebars for instance. There is currently no effective means available to protect the helmet shell from this type of low-force impact damage.
Accordingly, it is an object of the present invention to provide a device to modify air flow around the back and sides of a helmet.
It is another object of the present invention to provide a means of low-force impact protection for the helmet itself.
It is a further object of the present invention to provide a means for the user to adjust the position of the air flow interrupters as desired.
It is a still further object of the present invention to provide a means of changing the appearance of the user""s helmet if he so desires.
The present invention is a method of protecting a helmet shell and interrupting airflow around a helmet utilizing a removable flow interrupter strip. The strip is constructed so that it can be applied to a helmet after manufacture of the helmet shell and assembly of the helmet itself. In the preferred embodiment, the strip comprises a main body that has a height of approximately one-quarter inch. The length of the strip is approximately eight to fourteen inches. The width of the preferred embodiment is approximately one-half inch. The exact dimensions of the strip are generally not crucial to the purpose of the invention. The only critical dimension is the height of the strip. When the strip is applied to the surface of a helmet, the height of the strip must be sufficient to interrupt air flow and to protect the helmet finish.
The strip includes attachment means comprising generally an adhesive backing so that the strip may be easily removably affixed to the helmet surface. The attachment means must have sufficient strength so that the strip does not separate from the helmet surface during normal use.
In addition to defining air flow around the helmet, the strip provides protection from damage from low-force impacts. Examples of these types of impacts are those that occur if a helmet falls from handlebars or if the helmet is dropped. The strip is not intended to provide increased protection for the user of the helmet, but the strip does provide protection for the appearance of the helmet.
An advantage of the present invention is that the air flow interrupter strip may be applied to the helmet following manufacture of the helmet.
Another advantage of the present invention is that the strip can be removed and replaced by a user.
A still further advantage of the present invention is that the strip is easily and inexpensively manufactured.
These and other objects and advantages of the present invention will become apparent to those skilled in the art in view of the description of the best presently known mode of carrying out the invention as described herein and as illustrated in the drawings.